Method and apparatus to manufacture a rigid polymer panel having integrally formed optical quality surfaces

Abstract

A continuous polymer sheet casting apparatus includes first and second endless belts positioned in face to face relationship to each other for a portion of their lengths to form between their inside surfaces a mold cavity for molding a polymeric sheet therebetween, and a container in fluid communication with the mold cavity, the container configured to introduce a liquid monomer or liquid polymer and curing agent and/or initiator to the cavity for polymerization therein; a controlled cooling apparatus in thermal communication with the mold cavity, configured to cool and solidify the polymeric sheet as it moves through the mold cavity, wherein either the first, the second, or the first and second endless belts include a microstructured optical quality tool area on at least a portion of said belt or belts. A mold and process for molding is also disclosed.

1 . A continuous casting apparatus for polymeric sheet comprising:
 first and second endless belts, positioned in face to face relationship to each other for at least a portion of their lengths, forming between their inside surfaces a mold cavity for molding the polymeric sheet therebetween;   a container in fluid communication with the mold cavity, the container configured to introduce a liquid monomer and curing agent or liquid polymer to the mold cavity; and   a controlled cooling apparatus in thermal communication with the mold cavity, configured to cool and solidify the polymeric sheet as it moves through the mold cavity, wherein either the first, the second, or the first and second endless belts include a microstructured optical quality tool area on at least a portion of said belt or belts.   
     
     
         2 . The continuous casting apparatus of  claim 1 , wherein as the liquid monomer or liquid polymer flows into said mold it will be molded with the microstructured optical quality tool area such that when said polymer is cooled and solidified it forms a relatively rigid sheet having a microstructured surface that is a mirror image of the microstructured optical quality tool area. 
     
     
         3 . The continuous casting apparatus of  claim 1 , wherein said mold cavity lies in an approximately horizontal plane. 
     
     
         4 . The continuous casting apparatus of  claim 3 , wherein the first belt is an upper belt and the second belt is a lower belt and the lower belt comprises the microstructured optical quality tool area. 
     
     
         5 . A polymer casting apparatus for forming a relatively rigid polymer panel having a microstructured optical quality tool area on at least a portion of one side of said panel comprising:
 two molding members positioned in face to face relationship to each other defining a mold cavity therebetween;   means for introducing a liquid monomer or polymer into said mold cavity; and   means for controlling cooling and solidifying said polymer in said mold cavity;   wherein at least one of said mold members has a tool area defining a microstructured surface which is filled by said liquid monomer or polymer, and when solidified the panel produced thereby has a microstructured optical quality surface that is a mirror image of said tool area.   
     
     
         6 . The polymer casting apparatus of  claim 5 , further comprising means for affecting the spacing between said surfaces to affect the thickness of a polymer sheet formed therebetween. 
     
     
         7 . The polymer casting apparatus of  claim 5 , further comprising controlled cooling means for effecting cooling and solidifying of the polymer as it moves through the mold cavity. 
     
     
         8 . The polymer casting apparatus of  claim 5 , wherein the molding members are plates that are configured to engage in an alignment to form the mold cavity therebetween. 
     
     
         9 . The polymer casting apparatus of  claim 5 , wherein the molding members are rotating belts configured to form a molding cavity between belt surfaces. 
     
     
         10 . A process for making a relatively rigid polymeric panel having a microstructured surface on at least one area on said panel, the process comprising:
 casting a liquid monomeric or polymeric feed into a mold cavity, said cavity being defined by two continuously moving members;   passing a microstructured tool area on at least a portion of one of said continuously moving members and polymerizing and solidifying the liquid monomeric or polymeric feed as it is moved through said mold cavity by converting the monomeric or polymeric feed to a solid polymer and withdrawing said solid polymer from said mold cavity whereby at least one surface of said polymer will have a microstructured optical quality feature formed thereon.   
     
     
         11 . The process of  claim 10 , further comprising flowing monomer or polymer into a reservoir prior to casting it into a mold cavity. 
     
     
         12 . The process of  claim 10 , further comprising polymerizing the monomer in the mold cavity. 
     
     
         13 . The process of  claim 10 , wherein the liquid monomer or liquid polymer comprises an acrylate. 
     
     
         14 . The process of  claim 10 , wherein the liquid monomer or liquid polymer is combined with an initiator or curing agent, or both. 
     
     
         15 . The process of  claim 10 , wherein both members include a microstructured tool area that is passed over the monomeric or polymeric feed. 
     
     
         16 . The process of  claim 10 , wherein at least one member comprises a plurality of alternating smooth areas and microstructured tool areas for continuously making both smooth and microstructured panels. 
     
     
         17 . The continuous casting apparatus of  claim 1 , wherein a smooth area is 50 to 99% of the total area of the first or second belt, with the remainder being the microstructured tool area. 
     
     
         18 . The process of  claim 10 , wherein the solid polymer is in the form of a panel:
 and the panel has the microstructured surface formed thereon.   
     
     
         19 . The process of  claim 18 , wherein the liquid monomer or liquid polymer comprises an acrylate. 
     
     
         20 . The process of  claim 18 , wherein the panel is an LED light cover.